Azure VM --os-disk-size-gb partition, format and mount

If you are using Azure VM --os-disk-size-gb parameter to increase the size of the OS disk, you need to partition, format and mount to use it.

Check the current status with

 fdisk -l

 df -Th 

Step 1: Create a partition (See sample output below)

 sudo fdisk /dev/sda

(use n to create new partition, and follow prompts)

Step 2: Refresh partition table
 sudo partprobe

Step 3: Format the new partition, get the name from step 1 or use fdisk -l 

 mkfs.xfs /dev/sda3 

Step 4: Mount 

 mkdir /mnt/shared

 mount /dev/sda3 /mnt/shared/  

Step 5: Verify  

 df -Th 

Step 6: Edit the /etc/fstab to automatically mount when restarted 

 vi  /etc/fstab

Append line /dev/sda3 /mnt/shared xfs defaults 0 0  . Please note the filesystem type "xfs" is used as it was formatted in "xfs" in Step 3. You could use other formats as well based on your requirements .

                                                                                                                               

#                                                                                                                              

# /etc/fstab                                                                                                                   

# Created by anaconda on Wed Dec 19 23:06:16 2018                                                                              

#                                                                                                                              

# Accessible filesystems, by reference, are maintained under '/dev/disk'                                                       

# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info                                                    

#                                                                                                                              

UUID=fdb125e2-1ce5-4b7a-98db-88c0f66a86ee /                       xfs     defaults        0 0                                  

UUID=d4c5a046-3513-4ff0-a955-621311869210 /boot                   xfs     defaults        0 0                                  

/dev/sda3 /mnt/shared xfs defaults 0 0     

Sample Output:

[root@azvm azureusr]# fdisk /dev/sda

The device presents a logical sector size that is smaller than

the physical sector size. Aligning to a physical sector (or optimal

I/O) size boundary is recommended, or performance may be impacted.

Welcome to fdisk (util-linux 2.23.2).

Changes will remain in memory only, until you decide to write them.

Be careful before using the write command.

Command (m for help): n

Partition type:

   p   primary (2 primary, 0 extended, 2 free)

   e   extended

Select (default p): 

Using default response p

Partition number (3,4, default 3): 

First sector (62914560-125829119, default 62914560): 

Using default value 62914560

Last sector, +sectors or +size{K,M,G} (62914560-125829119, default 125829119): 

Using default value 125829119

Partition 3 of type Linux and of size 30 GiB is set

Command (m for help): w

The partition table has been altered!

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error 16: Device or resource busy.

The kernel still uses the old table. The new table will be used at

the next reboot or after you run partprobe(8) or kpartx(8)

Syncing disks.

[root@azvm azureusr]# partprobe

[root@azvm azureusr]# fdisk -l

Disk /dev/sda: 64.4 GB, 64424509440 bytes, 125829120 sectors

Units = sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 4096 bytes

I/O size (minimum/optimal): 4096 bytes / 4096 bytes

Disk label type: dos

Disk identifier: 0x000eba6a

   Device Boot      Start         End      Blocks   Id  System

/dev/sda1   *        2048     1026047      512000   83  Linux

/dev/sda2         1026048    62914559    30944256   83  Linux

/dev/sda3        62914560   125829119    31457280   83  Linux

Disk /dev/sdb: 751.6 GB, 751619276800 bytes, 1468006400 sectors

Units = sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 4096 bytes

I/O size (minimum/optimal): 4096 bytes / 4096 bytes

Disk label type: dos

Disk identifier: 0x3fde6d89

   Device Boot      Start         End      Blocks   Id  System

/dev/sdb1             128  1468004351   734002112   83  Linux

[root@azvm azureusr]# df -Th

Filesystem     Type      Size  Used Avail Use% Mounted on

/dev/sda2      xfs        32G  5.8G   26G  19% /

devtmpfs       devtmpfs  186G     0  186G   0% /dev

tmpfs          tmpfs     186G     0  186G   0% /dev/shm

tmpfs          tmpfs     186G  9.5M  186G   1% /run

tmpfs          tmpfs     186G     0  186G   0% /sys/fs/cgroup

/dev/sda1      xfs       521M   68M  454M  13% /boot

/dev/sdb1      ext4      740G   76M  703G   1% /mnt/resource

tmpfs          tmpfs      38G     0   38G   0% /run/user/1000

[root@azvm azureusr]# mkfs.xfs /dev/sda3 

meta-data=/dev/sda3              isize=512    agcount=4, agsize=1966080 blks

         =                       sectsz=4096  attr=2, projid32bit=1

         =                       crc=1        finobt=0, sparse=0

data     =                       bsize=4096   blocks=7864320, imaxpct=25

         =                       sunit=0      swidth=0 blks

naming   =version 2              bsize=4096   ascii-ci=0 ftype=1

log      =internal log           bsize=4096   blocks=3840, version=2

         =                       sectsz=4096  sunit=1 blks, lazy-count=1

realtime =none                   extsz=4096   blocks=0, rtextents=0

[root@azvm azureusr]# mkdir /mnt/shared

[root@azvm azureusr]# mount /dev/sda3 /mnt/shared/ 

[root@azvm azureusr]# df -Th

Filesystem     Type      Size  Used Avail Use% Mounted on

/dev/sda2      xfs        30G  5.4G   25G  19% /

devtmpfs       devtmpfs  174G     0  174G   0% /dev

tmpfs          tmpfs     174G     0  174G   0% /dev/shm

tmpfs          tmpfs     174G  9.1M  174G   1% /run

tmpfs          tmpfs     174G     0  174G   0% /sys/fs/cgroup

/dev/sda1      xfs       497M   65M  433M  13% /boot

/dev/sdb1      ext4      689G   73M  654G   1% /mnt/resource

tmpfs          tmpfs      35G     0   35G   0% /run/user/1000

/dev/sda3      xfs        30G   33M   30G   1% /mnt/shared